What version of myst-parser are you using?

2.0.0

What version dependencies are you using?

Name: Sphinx
Version: 7.2.6

Name: docutils
Version: 0.20.1

What operating system are you using?

Mac

Describe the Bug

When internal linking to a fourth level header (#### Fourth Level Header) using the syntax [link text](#fourth-level-header), upon doc compilation myst throws this error the first time during compilation: WARNING: 'myst' cross-reference target not found: 'fourth-level-header' [myst.xref_missing]. However the link works when inspecting and testing the compiled docs.

Expected Behavior

An error will not be thrown.

To Reproduce

Try to compile this file below with a command such as sphinx-build -b html src build:

# First

[link to first](#first)

## Second

[link to second](#second)

### Third

[link to third](#third)

#### Fourth

[link to fourth](#fourth)

results in error:

WARNING: 'myst' cross-reference target not found: 'fourth' [myst.xref_missing]